Rootstock selection moderates the effect of rising temperatures through drought tolerance and modulation of stomatal conductance

Abstract

Climate change is increasing crop evapotranspiration and reducing water availability, especially in the Mediterranean area. The use of grapevine rootstocks (Vitis spp.) is a great modulator of drought tolerance and vigor. Despites these being well characterized in some aspects, the performance of the different rootstocks under climate change conditions is largely unexplored. The aim of this study was to test the effect of increased temperature on water use of water use traits of grapevines on different rootstocks.

In this experiment, four rootstocks (420A, FERCAL, 110R and 140Ru) grafted with Grenache were grown with either ambient or elevated (+4oC) temperature under well-watered conditions. The four rootstocks were also characterized under a drought cycle where irrigation was withheld until stomatal closure. Temperature increased net assimilation (A), transpiration (E) and stomatal conductance (gs), with the rootstocks showing different gs rates. Water consumption (E and gs) of 140Ru was not increased under elevated temperature, suggesting a good adaptation of this genotype to these conditions. Rootstock 140R had the lowest anisohydricity (estimated as the difference between Ψ midday stem and Ψ predawn), while 420A had the highest. Rootstock 110R needed greater soil water tension to close their stomata, while 420A closed stomata under the lowest tension of all.

Being 140R and 110R two rootstocks known as drought tolerant, 110R showed the greatest tolerance to drying soils while 140Ru showed a modulation of water consumption desirable under rising temperatures.